SYNOPSIS

DESCRIPTION

The getgrnam() function shall search the group database for an entry with a matching name.

The getgrnam() function need not be thread-safe.

Applications wishing to check for error situations should set errno to 0 before calling getgrnam(). If
getgrnam() returns a null pointer and errno is set to non-zero, an error occurred.

The getgrnam_r() function shall update the group structure pointed to by grp and store a pointer to that
structure at the location pointed to by result. The structure shall contain an entry from the group database with a matching
name. Storage referenced by the group structure is allocated from the memory provided with the buffer
parameter, which is bufsize bytes in size. A call to sysconf(_SC_GETGR_R_SIZE_MAX) returns either -1 without changing
errno or an initial value suggested for the size of this buffer. A null pointer is returned at the location pointed to by
result on error or if the requested entry is not found.

RETURN VALUE

The getgrnam() function shall return a pointer to a struct group with the structure defined in <grp.h> with a matching entry if one is found. The getgrnam() function shall
return a null pointer if either the requested entry was not found, or an error occurred. If the requested entry was not found,
errno shall not be changed. On error, errno shall be set to indicate the error.

The application shall not modify the structure to which the return value points, nor any storage areas pointed to by pointers
within the structure. The returned pointer, and pointers within the structure, might be invalidated or the structure or the storage
areas might be overwritten by a subsequent call to getgrent(), getgrgid(), or getgrnam(). The returned pointer, and pointers within the structure,
might also be invalidated if the calling thread is terminated.

The getgrnam_r() function shall return zero on success or if the requested entry was not found and no error has occurred.
If any error has occurred, an error number shall be returned to indicate the error.

ERRORS

The getgrnam() and getgrnam_r() functions may fail if:

[EIO]

An I/O error has occurred.

[EINTR]

A signal was caught during getgrnam().

[EMFILE]

All file descriptors available to the process are currently open.

[ENFILE]

The maximum allowable number of files is currently open in the system.

The getgrnam_r() function may fail if:

[ERANGE]

Insufficient storage was supplied via buffer and bufsize to contain the data to be referenced by the resulting
group structure.

The following sections are informative.

EXAMPLES

Note that sysconf(_SC_GETGR_R_SIZE_MAX) may return -1 if there is no hard limit on the size of the buffer needed to store
all the groups returned. This example shows how an application can allocate a buffer of sufficient size to work with
getgrnam_r().

RATIONALE

FUTURE DIRECTIONS

SEE ALSO

CHANGE HISTORY

Issue 5

Normative text previously in the APPLICATION USAGE section is moved to the RETURN VALUE section.

The getgrnam_r() function is included for alignment with the POSIX Threads Extension.

A note indicating that the getgrnam() function need not be reentrant is added to the DESCRIPTION.

Issue 6

The getgrnam_r() function is marked as part of the Thread-Safe Functions option.

In the DESCRIPTION, the note about reentrancy is expanded to cover thread-safety.

In the SYNOPSIS, the optional include of the <sys/types.h> header is
removed.

The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:

The requirement to include <sys/types.h> has been removed. Although <sys/types.h> was required for conforming implementations of previous POSIX
specifications, it was not required for UNIX applications.

In the RETURN VALUE section, the requirement to set errno on error is added.